Field of the Invention
The invention relates to an image capturing apparatus, an image processing method, and a non-transitory computer-readable storage medium.
Description of the Related Art
Image capturing units can execute so-called development processing that, for example, converts a raw image (RAW image) shot by an image sensor into signals composed of luminance and chrominance by applying de-Bayer processing (demosaicing processing) to the raw image, removes noise from the signals, corrects optical distortion, and optimizes the image. The luminance signals and chrominance signals that have undergone such development processing are generally recorded in a recording medium in a compressed and encoded state.
There are also image capturing apparatuses that can record RAW images. Although an enormous amount of data is needed to record RAW images, advanced users use the RAW images by preference as the RAW images have the advantage of minimizing correction to and deterioration of original images and being editable after shooting.
Such RAW images can be recorded not only as still images, but also as moving images. In recording RAW moving images, it is necessary to perform control for compressing a data amount to a desired code amount so that moving images of a certain period can be recorded in a predetermined recording medium. However, when the data amount exceeds the speed of data transfer to the predetermined recording medium due to a failure to appropriately perform code amount control and quantization control, data corruption occurs in the recording medium. In the case of recording of still images, there is no notion of guarantee on real-time reproduction; on the other hand, in the case of recording of moving images, proper reproduction cannot be performed on a reproduction apparatus when a bitrate of the moving images exceeds a bitrate that guarantees real-time reproduction, even if the moving images have been written to the recording medium. To prevent the occurrence of these problems, image capturing apparatuses need to perform the code amount control and the quantization control appropriately.
Furthermore, a data amount could possibly exceed the speed of data transfer to a predetermined recording medium not only during recording of moving images, but also during continuous shooting and recording of still images. Japanese Patent Laid-Open No. 2007-97145 suggests an image capturing apparatus that continuously shoots and records two types of still images, that is to say, RAW still images and still images that are obtained by developing the RAW images and compressing and encoding the developed RAW images using a compression technique (e.g., JPEG and the like); this image capturing apparatus performs quantization control with respect to the still images that have been compressed and encoded.
According to the image capturing apparatus suggested by Japanese Patent Laid-Open No. 2007-97145, during continuous shooting and recording of still images, recording is performed using a combination of a lossless compressed RAW image using DPCM conversion and a JPEG image, and therefore quantization control for bitrate adjustment cannot be performed with respect to the lossless compressed RAW images. This gives rise to the possibility that a data amount exceeds the speed of data transfer to a predetermined recording medium.